Biscuit Epsiode

Parliament was first asked to vote on the idea as early as 1824, but on that occasion rejected the notion completely. Three times more over the next century the idea was raised, but never came anywhere very close to being adopted.

Then in 1961, the Conservative government of Harold McMillan commissioned some further research into the question. The report recommended decimalization, but this wasn't the answer that McMillan wanted and so he did nothing about it. But after a change of government in 1964, Labour PM Harold Wilson declared that it was going to happen.

It was two years before a Bill was introduced and that Bill took three years to get through Parliament because the Conservatives opposed it, but it was finally passed in 1969 and decimal currency became a reality two years later.

Lots of wallowing in nostalgia for me, thanks to chrisboote.
By the way, 10 bob was known as 'half a knicker'. Also, half a crown was often called, half a dollar, as at one time, it had the same value as 50 cents.

The use of (k)nicker for a pound dates back to about 1900, but the best that the usual sources can do is to suggest that it may be horse racing slang.

Very speculatively, it's been noted that at this time USians sometimes referred to a $5 bill as a nickel (by analogy with the 5c coin, which is rather more often referred to as a nickel). And at the time of which we're speaking, $5 was approximately equivalent to one pound. This isn't a very satisfactory explanation though, and seems unlikely to be correct.

Some sources on slang allege that the £2 coin is commonly known as a pair of knickers. A small prize for anyone who's ever actually heard this.

I'm FAIRLY sure that 'half a knicker' for ten bob was because 'a knicker' was a pound
Why? Well, nobody knows
But the most likely explanation is horseracing slang; a nicker originally being a losing bet (from ~1850) - nicker = neigh = nay

The Tote Museum quotes 1871 as the first use of 'nicker' being a pound, claiming that "all racecourse bets were changed in that year to be a minimum of £1", but this seems incredibly expensive to me - at a time when a day trip to Epsom Races, including entrance fee, was a shilling - and makes me think that they have it wrong